The short answer
Lead is heavier, softer and easier to shape around awkward details, which is why it dominates flashings, valleys and small flat roofs. Zinc is lighter, stiffer and suited to larger standing-seam roofs and cladding. Both can last a century in the right conditions. Lead usually costs more per square metre of flat roof, and zinc gives a modern, cooler finish.
Two metals, two characters
Lead is dense and soft. It can be dressed by hand into almost any shape, and it stays where it is put. That makes it the traditional choice for awkward places: the valley between two slopes, a chimney flashing, the cheeks of a dormer, a bay window roof. It is also forgiving of an uneven base.
Zinc is lighter and harder. It arrives in long coils or sheets, is folded into standing seams and holds a crisp line. It is used on whole roofs and on wall cladding, particularly on modern extensions, and it is much less common on a Victorian terrace. It is less happy wrapped around small, irregular details, because repeated bending can crack it.
Lifespan on paper and in practice
Lead is the longer-established of the two. MyJobQuote, in a guide dated 22 September 2026, says lead flashing that is correctly installed can last over 80 years, and over 100 years for higher codes. Less lists lead on a flat roof at 50 to 100 years.
The zinc maker VMZINC says a roof that is correctly designed and installed can last in excess of 100 years, though the life can occasionally drop to 60 years. A contractor quoted by HomeBuilding in 2020 gave 60 to 100 years. Those are manufacturer and trade figures, not promises, and either metal can fail far sooner if it is laid badly.
In practice the weak points are shared. Poor fixings, trapped moisture underneath and ponding water shorten the life of both. Our page on how long a lead roof lasts goes into those factors.
Cost, and what drives it
MyBuilder's flat roof guide, updated on 21 August 2026, gives typical national installed prices of £150 to £200 or more per m² for lead. It publishes no matching zinc figure, so a direct price comparison would be guesswork. What can be said is that lead is heavy, takes skilled hand work and costs more as a raw material, while zinc asks for careful design and detailing on a complicated roof.
On a small job, such as a porch roof or a short run of flashing, the labour tends to outweigh the metal. On a large plain roof the sheet price and the speed of laying matter more. Access, the substrate and the number of junctions affect both. After a visit you get one written total for the job, and it is worth checking whether VAT and scaffolding sit inside any other figure you hold.
Looks, weathering and staining
New lead is a bright, soft silver that darkens quickly to a matt grey as it forms a protective oxide film. Zinc starts as a bright blue-grey and settles to a deeper, even grey. Many people like how both blend into stone, slate and brick, and neither needs painting.
During its first months, lead can wash a white powder onto the surfaces below. That is described in our page on white staining on lead, and a patination oil can head it off, as covered in lead patination.
On a conservation-area terrace or a listed building, lead is usually the metal the conservation officer expects to see, and swapping to another metal may need consent. Check with Swindon Borough Council's planning team before assuming zinc will be accepted.
Which one for which job
For flashings, soakers, valleys, small dormers and bay roofs, lead is the practical choice and has the longest track record. Our bay and porch roofs page shows the typical detail.
For a larger flat or low-pitch roof on a modern extension, zinc is worth pricing beside lead, since it can be laid in long standing-seam sheets with fewer joints. For a small roof over a bay or a kitchen, lead is often the simpler answer, and where joins are needed, lead welding keeps the surface watertight without solder. Anyone tempted to try the small stuff themselves should read DIY lead flashing first.
Weight, noise and movement
Lead weighs a great deal. Code 5, at 2.24 mm, is about 25.40 kg per m², which is why it needs a solid deck and sound timbers beneath. Zinc is a much lighter sheet, so on a long roof it puts less load on the structure and is easier to carry up. Weight is worth checking if an older roof already sags.
Metal roofs are sometimes expected to be noisy in rain. Laid on a proper deck with an underlay, both lead and zinc are quiet; a drumming sound usually means loose sheet or a hollow base, not the metal itself.
Movement differs too. Lead is soft and tolerant but creeps on a slope, while zinc is stiff, expands in long runs and needs its seams and clips to allow for it. Either way the designer, not the metal, decides how long the roof lasts. See lead roofing for the wider range of leadwork we cover.
Settling the choice
If you cannot decide, send photographs of the roof or ask for a survey. We explain which metal suits which part of the building and why, and the preferred option goes into the written quote. The scale of the work should match the fault, and if a patch of existing lead is sound, we will say so instead of proposing a new covering.
Our workmanship guarantee lasts ten years and is written down, and we tidy up before we go. Call 01793 626096 or send a message when you are ready. For flat roofs in particular, our page on lead flat roof repair shows what a repair involves before anyone talks about replacement.